Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Development, Field Testing, and Implementation of Improved Bridge Parapet Designs, Final Report
A total of 22 test parapets was constructed as part of this project to evaluate different approaches to address premature cracking. The experiments included the use of deeper saw cuts through glass fiber reinforced polymer (GFRP) reinforcement or field cut steel reinforcement, with the saw cut depth increased from 1 ½ inches (38 mm) to 3 ½ inches (89 mm). Another experimental modification was the use of polypropylene fibers in the mixture at two different dosage rates, 1 lb/yd3 (0.59 kg/m3) and 2 lb/yd3 (1.19 kg/m3). The research team monitored bridge parapets during and immediately after construction. This included instrumentation with embedded maturity sensors to capture temperature history of the parapets, using Command Center technology. Researchers also observed and documented parapet construction. It was important to note any constructability issues that may arise that may be related to the proposed solutions, since they would potentially impact the cost of implementation. Crack surveys were performed once formwork was removed and sawcutting had been completed. The stiffness gain of parapets and joint cracking were monitored using ultrasonic pulse velocity (UPV) technology. While all of the eight control bridges showed mid-panel cracking, only four of the twelve experimental bridges had mid-panel cracking. Both parapets with Vandal Protection Fence (VPF) posts showed cracks near the posts. The main purpose of using GFRP or field cut steel reinforcement with the 3.5 inch (89 mm) deep saw cut is to create a weakened plane at the control joint through the gap provided in the reinforcement, in order initiate cracking at the joints and reduce the risk of cracking elsewhere on the parapet. From the data gathered, this modification allowed more joints to crack at early stages, and prevented uncontrolled cracking. The parapets with fibers showed no measurable improvement over the parapets without fibers in regards to preventing shrinkage and temperature cracking. Reducing the joint spacing over negative tension areas was found to reduce uncontrolled bridge parapet cracking. However, since the experimental parapets with the reduced joint spacing were coupled with another modification of either the polypropylene fibers or the deeper saw cut, it was hard to determine if this alone would solve uncontrolled bridge parapet cracking.
Development, Field Testing, and Implementation of Improved Bridge Parapet Designs, Final Report
A total of 22 test parapets was constructed as part of this project to evaluate different approaches to address premature cracking. The experiments included the use of deeper saw cuts through glass fiber reinforced polymer (GFRP) reinforcement or field cut steel reinforcement, with the saw cut depth increased from 1 ½ inches (38 mm) to 3 ½ inches (89 mm). Another experimental modification was the use of polypropylene fibers in the mixture at two different dosage rates, 1 lb/yd3 (0.59 kg/m3) and 2 lb/yd3 (1.19 kg/m3). The research team monitored bridge parapets during and immediately after construction. This included instrumentation with embedded maturity sensors to capture temperature history of the parapets, using Command Center technology. Researchers also observed and documented parapet construction. It was important to note any constructability issues that may arise that may be related to the proposed solutions, since they would potentially impact the cost of implementation. Crack surveys were performed once formwork was removed and sawcutting had been completed. The stiffness gain of parapets and joint cracking were monitored using ultrasonic pulse velocity (UPV) technology. While all of the eight control bridges showed mid-panel cracking, only four of the twelve experimental bridges had mid-panel cracking. Both parapets with Vandal Protection Fence (VPF) posts showed cracks near the posts. The main purpose of using GFRP or field cut steel reinforcement with the 3.5 inch (89 mm) deep saw cut is to create a weakened plane at the control joint through the gap provided in the reinforcement, in order initiate cracking at the joints and reduce the risk of cracking elsewhere on the parapet. From the data gathered, this modification allowed more joints to crack at early stages, and prevented uncontrolled cracking. The parapets with fibers showed no measurable improvement over the parapets without fibers in regards to preventing shrinkage and temperature cracking. Reducing the joint spacing over negative tension areas was found to reduce uncontrolled bridge parapet cracking. However, since the experimental parapets with the reduced joint spacing were coupled with another modification of either the polypropylene fibers or the deeper saw cut, it was hard to determine if this alone would solve uncontrolled bridge parapet cracking.
Development, Field Testing, and Implementation of Improved Bridge Parapet Designs, Final Report
A. Kalabon (Autor:in) / L. Hedges (Autor:in) / N. Delatte (Autor:in)
2015
126 pages
Report
Keine Angabe
Englisch
Soil Sciences , Construction Equipment, Materials, & Supplies , Transportation , Transportation & Traffic Planning , Construction Materials, Components, & Equipment , Construction Management & Techniques , Structural Analyses , Ohio , Bridge parapets , Joint details , Deeper saw cuts , Polypropylene fibers , Concrete , Cracking , Improved parapet , Designs , Fibers , Steel reinforcement , Construction project , Glass Fiber Reinforced Polymer (GFRP)
Development, Field Testing, and Implementation of Improved Bridge Parapet Designs
| British Library Online Contents | 2014
Design and development of improved bridge parapet
| Engineering Index Backfile | 1965
Uncontrolled Concrete Bridge Parapet Cracking
| NTIS | 2013